Rolling wheel support structure for crawler traveling apparatus

ABSTRACT

A rolling wheel support structure for crawler traveling apparatus includes rotary shafts rotatably supporting rolling wheels which roll on a ground contacting side of an inner circumferential surface of an endless crawler, a track frame supporting the rotary shafts thereon, and a buffer member formed of an elastic material and provided between the track frame and a rotary shaft.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a rolling wheel support structure forcrawler traveling apparatus used as traveling apparatus for anagricultural machine, a construction machine or the like.

[0003] 2. Description of the Prior Art

[0004] This kind of crawler traveling apparatus is formed by providing adriving wheel and a driven wheel at front and rear sides of a trackframe, and a plurality of rolling wheels on a lower portion of the trackframe, and wrapping around these wheels a metal crawler provided with amultiplicity of iron shoes on outer circumferential portions of chainlinks or an elastic crawler made of an elastic material, such as rubber.This kind of crawler traveling apparatus is designed so as to improvethe traveling characteristics thereof with respect to a soft land and adesolate land by increasing an area of the crawler contacting a groundsurface to reduce a ground pressure.

[0005] Since the crawler traveling apparatus has a high frequency oftraveling on a soft land and a desolate land, large vibration of thetraveling apparatus occurs due to the irregularity of the groundsurface, a problem of the deterioration of a riding comfort arises.Therefore, it is an important problem in the development of crawlertraveling apparatus to improve the riding comfort by eliminating thecauses of such vibration.

[0006] The measures which have heretofore been taken to eliminate thecauses of such a vibration include the measures disclosed in, forexample, Japanese Unexamined Utility Model Publication No. 42503/1976.These measures use a structure formed by fixing an elastic material,such as rubber on outer circumferential surfaces of rolling wheels byburning; and providing protective covers on outer circumferentialportions of this elastic material. Owing to this structure, the elasticmaterial provided between an inner circumferential surface of a crawlerand the rolling wheels absorbs such vibration, and the riding comfortcan be improved to some extent.

[0007] However, in this structure, since the elastic material isprovided on the outer circumferential surfaces of the rolling wheels,the protective covers are needed. Even when the protective covers areprovided in practice, the occurrence of abrasion and defects of therolling wheels cannot be avoided since the rolling wheels always roll onthe crawler. Moreover, burning of the elastic material on the rollingwheels causes an increase in manufacturing cost which is a drawback ofthese techniques.

[0008] In view of these problems, it is an object of the presentinvention to provide a rolling wheel support structure for crawlertraveling apparatus, capable of effectively improving the riding comfortof a crawler by properly absorbing the vibration thereof due to theirregularity of a ground surface.

SUMMARY OF THE INVENTION

[0009] According to one aspect of the present invention, there isprovided a: rolling wheel support structure for crawler travelingapparatus, including rotary shafts rotatably supporting rolling wheelswhich roll on a ground contacting side of an inner circumferentialsurface of an endless crawler, a track frame supporting the rotaryshafts, and a buffer member made of an elastic material and providedbetween the track frame and a rotary shaft.

[0010] According to the above structure, the vibration of the crawlerdue to the irregularity of the ground surface is properly absorbed inthe buffer member provided between the track frame and the rotary shaft,and the riding comfort is improved. Since the buffer members do notdirectly contact the inner circumferential surface of the crawler,deterioration of the buffer member caused by abrasion or the likedecreases.

[0011] In this structure, it is recommended that the rotary shaft beprovided on the track frame so that the rotary shaft can be verticallymoved; a receiving member be provided on the rotary shaft; and a buffermember be provided between an upper portion of the receiving member anda lower portion of the track frame. This enables a vibration-proofstructure for the crawler traveling apparatus to be obtained simply andinexpensively.

[0012] Accoreding to another aspect of the present invention, there isprovided a rolling wheel support structure for crawler travelingapparatus, including a swinging member rotatably supporting a rollingwheel which rolls on a ground contacting side of an innercircumferential surface of an endless crawler, a pivot pivotablysupporting the swinging member, a track frame supporting the pivot, anda buffer member provided between the track frame and the pivot.

[0013] According to the above structure, the vibration of the crawlerdue to the irregularity of a ground surface comes to be properlyabsorbed in the buffer member provided between the track frame and thepivot, so that the riding comfort is improved.

[0014] In this structure, it is recommended that the track frame isprovided with a cylindrical support member capable of being fittedaround the buffer member, and that the buffer member has a cylindricalshape such that the pivot can be fixed into the buffer member so as tobe impossible to turn relative to the buffer member around the axisthereof.

[0015] Owing to this structure, the vibration of the crawler can beabsorbed in the buffer member with the swinging member maintained in apivotable condition.

[0016] In this case, it is preferable that the swinging member fixingshaft is formed to a shape of a square shaft and an inner surface of thebuffer member is formed to a shape in conformity with the shaft incross-section.

[0017] Moreover, the buffer member preferably includes larger-diameterportions and smaller-diameter portions alternately in the axialdirection thereof.

[0018] Although the buffer member can be provided correspondingly to allthe rolling wheels, it may also be provided correspondingly to only arolling wheel provided at a front or rear portion of the crawlertraveling apparatus, or correspondingly to only a rolling wheel providedat a longitudinally intermediate portion of the crawler travelingapparatus.

[0019] When a working machine such as a combine is swung, a front orrear portion of a crawler traveling apparatus stands firm, and themachine as a whole swings longitudinally in some cases. However, whenthe buffer member is provided in a rolling wheel positioned at the frontportion or rear portion of the crawler traveling apparatus, such aswinging phenomenon can be avoided by the buffer member. When the buffermember is provided on a rolling wheel at a longitudinally intermediateportion of the crawler traveling apparatus, the rolling wheel can bepressed against the inner circumferential surface of the endless crawlerby the buffer member, whereby a ground pressure of the longitudinallyintermediate portion of the crawler partly increase, and a pivotal orswinging movement of the working machine around the mentioned portion ofthe crawler to be carried out smoothly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a side view of a rolling wheel support structureaccording to an embodiment of the present invention;

[0021]FIG. 2 is a general side view of a crawler traveling apparatus;

[0022]FIG. 3 is a side view of a rolling wheel support structureaccording to another embodiment;

[0023]FIG. 4 is a side view showing a modified example of the embodimentof FIG. 3;

[0024]FIG. 5 is a sectioned front view of a rolling wheel supportstructure according to still another embodiment;

[0025]FIG. 6 is a sectioned front view of a principal portion of amodified example of the embodiment of FIG. 5;

[0026]FIG. 7 is a side view of a rolling wheel support structureaccording to still another embodiment;

[0027]FIG. 8 is a side view of a principal portion of the embodiment ofFIG. 5;

[0028]FIG. 9 is a front view of a buffer member;

[0029]FIG. 10 is a side view showing a buffer member according toanother embodiment;

[0030]FIG. 11 is a side view of a rolling wheel support structureaccording to another embodiment; and

[0031]FIG. 12 is a sectional view taken along the line B-B shown witharrows in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The modes of embodiment of the present invention will now bedescribed with reference to the drawings.

[0033]FIG. 2 shows a crawler traveling apparatus 1 employing a rollingwheel support structure according to the present invention. The crawlertraveling apparatus 1 is formed by providing a driven wheel 3 and adriving wheel 4 at front and rear portion of a track frame 2, and aplurality of rolling wheels 5 on a lower portion thereof, and wrappingan endless crawler 6 around these rolling wheels 3, 4, 5.

[0034] As the crawler 6, a metal crawler having iron shoes fixed onouter surfaces of a plurality of endlessly connected chain links, anelastic crawler endlessly formed out of an elastic material such asrubber, or the like are employed. The crawler 6 is driven by the drivingwheel 4 and formed so that the rolling wheels 5 roll on an innercircumferential surface of a ground contacting side portion of thecrawler.

[0035] The rolling wheels 5 are supported on the track frame 2 viarotary shafts 10 each of which is inserted in a vertically elongatedhole 11 formed in the track frame 2 as shown in FIG. 1 so that therotary shaft 10 can be vertically moved.

[0036] A disc-shaped receiving member 14 having a plate-shaped receivingelement 13 is fixed around the rotary shaft 10 or fitted therearound soas to be rotatable about an axis of the rotary shaft 10. Between anupper surface of the receiving element 13 and a lower surface of thetrack frame 2, a plate-shaped or block-shaped buffer member 15 formedout of an elastic material, such as rubber and urethane resin isinterposed.

[0037] Therefore, the rolling wheel 5 can be moved vertically withrespect to the track frame 2, and supported in a vertically elasticstate on the buffer member 15.

[0038] Consequently, when the crawler traveling apparatus I runs on aroad surface of a very high irregularity, the vibration of the travelingapparatus is absorbed properly by the buffer member 15, so that thevibration is prevented from being transmitted to a worker sitting in aworking machine on the crawler traveling apparatus as much as possible.

[0039] Since the buffer member 15 is held compactly around the rotaryshaft 10, more specifically, in an area of side projection of therolling wheel 5, the buffer member 15 does not substantially interferewith other rolling wheels and surrounding parts.

[0040] Although it is possible that this buffer member 15 be providedfor all the rolling wheels 5, it is also possible that the buffer member15 be provided for only a certain rolling wheel, for example, a rollingwheel at an intermediate, front, or rear portion of the crawlertraveling apparatus 1 with respect to the longitudinal directionthereof.

[0041] For example, when the buffer member 15 is provided for therolling wheel 5a positioned in a longitudinally intermediate portion ofthe crawler traveling apparatus 1 as shown in FIG. 2, it is preferablethat this rolling wheel 5a be disposed slightly lower than the otherrolling wheels 5 as shown by a two-dot chain line in the same drawing ina no-load condition (when a reaction force from the ground surface iszero).

[0042] This increases the ground pressure of the crawler 6 at a positioncorresponding to the rolling wheel 5a, thereby facilitating a pivotal orswinging movement of the crawler around this position, and improving theswinging performance of the crawler.

[0043] When the buffer member 15 is provided correspondingly to therolling wheel 5 positioned at the front or rear portion of the trackframe 2, the occurrence of a phenomenon seen in, for example, a combinein which, when the machine is swung, a front portion or a rear portionof a crawler traveling apparatus 1 stands firm to cause the machine as awhole to be longitudinally swung can be avoided. Therefore, the crawlertraveling apparatus 1 can be stably swung with a load left in thelongitudinally intermediate portion thereof.

[0044] The buffer member 15 may be bonded to the receiving element 13 orthe track frame 2, or the buffer member 15 may be positioned by screwinga bolt 17, which is inserted vertically through the receiving element 13and buffer member 15, to the track frame 2 as shown in FIG. 3. When thelatter arrangement is employed, the positioning of the buffer member 15can be done easily with a vertical movement of the rolling wheel 5 withrespect to the track frame 2 allowed. Moreover, a limit to a downwardmovement of the rolling wheel 5 can be regulated by the bolt 17.

[0045] As shown in FIG. 4, the bolt 17 may be provided so that the boltpasses through also the track frame 2 from the lower surface thereof,and is fixed by a nut 18 on the inner side of the track frame 2.

[0046]FIG. 5 shows another embodiment of the present invention. Areceiving member 14 in this embodiment includes a cylindrical shaftfixing portion 20 and flange portions 21 radially extending fromopposite axial ends of the shaft fixing portion 20. The shaft fixingportion 20 is vertically movably inserted through the track frame 2, anda rotary shaft 10 is inserted through a central portion of the shaftfixing portion 20.

[0047] The flange portions 21 are formed with thicker sections 21Aadjacent to root portions thereof, each of which protrudes towardopposing thicker section 21A, and an annular buffer member 15 isprovided between thicker sections 21A of the two flange portions 21. Theouter circumferential edges of the thicker sections 21A are formed withrounded or diagonally chamfered surfaces 21B.

[0048] In this embodiment, the receiving member 14 can be verticallymoved by a distance corresponding to a clearance S between the thickersection 21A of the flange portion 21 and track frame 2. Owing to thecompression of the buffer member 15 to absorb the vertical movement ofthe receiving member 14, the vibration of a crawler can be absorbedtherein.

[0049] Since the buffer member 15 is provided on the inner side of thetrack frame 2 and not exposed to the outside, surrounding parts rarelycontact the buffer member 15, and are rarely covered with mud, so thatthe early deterioration of the buffer member can be prevented.

[0050] Since outer circumferential edges of the thicker sections 21A arechamfered, even when the compressed buffer member 15 bulges into theclearance S and is pressed onto the edges of the thicker sections 21A,the buffer member 15 is prevented from being damaged.

[0051] As shown in FIG. 6, the thicker section 21A may be formed on oneof the flange portions 21. In this case, the thicker section 21A ispreferably formed to be slightly thicker than the thicker sections inthe above-described embodiment. In this case, it is also preferable thatan outer circumferential edge of the thicker section 21A be formed witha chamfered surface 21B.

[0052]FIGS. 7 and 8 show still another embodiment of the presentinvention.

[0053] This embodiment is formed by pivotably providing a swingingmember 25 to a track frame 2 and rotatably providing a rolling wheel 5to the swinging member 25 as shown in a section A of FIG. 2, with abuffer member 15 additionally provided between the swinging member 25and track frame 2.

[0054] More specifically, the track frame 2 is provided with acylindrically shaped support member 26 extending in the lateraldirection, a cylindrically shaped buffer member 15 is fitted into thesupport member 26, and a pivot 27 of the swinging member 25 is fittedrelatively non-rotatably into the buffer member 15.

[0055] The buffer member 15 is provided on the inner side thereof withan angled cylinder 28, which is in this embodiment formed of a hexagonalcylinder by way of example. On the other hand, the pivot 27 of theswinging member 25 is formed as an angled shaft (hexagonal shaft in theillustrated example) the shape of which is substantially identical withthat of the angled cylinder 28 so that the pivot 27 is fitted relativelynon-rotatably in the angled cylinder 28 for the buffer member 15. Theangled cylinder 28 is preferably formed of a material such as a metal ora reinforced plastic.

[0056] The buffer member 15 is formed to have an outer diameter slightlylarger than an inner diameter of the support member 26, and press-fittedinto the support member 26 so that a relative turning movement does notoccur between the two.

[0057] Therefore, the swinging member 25 can be turned in the range oftorsion of the buffer member 15. When the crawler traveling apparatusruns on a road surface of a high degree of irregularity, the vibrationof the traveling apparatus is properly absorbed owing to the compressionof the buffer member 15, and the riding comfort becomes excellent.

[0058] Since the buffer member 15 is compactly provided around the pivot27 of the swinging member 25, a large space for providing the buffermember 15 is not substantially needed.

[0059] As shown in FIG. 9, the buffer member 15 can be formed so as tohave larger-diameter portions 30 and smaller-diameter portions 31arranged alternately in the longitudinal direction thereof. In thiscase, the buffer member 15 can be compressed greatly in the radialdirection. Accordingly, an increase in the buffering effect can beexpected, and a heat dissipating performance becomes excellent.

[0060] The lengths a, b, a′, b′ of the larger-diameter portions 30 andsmaller-diameter portions 31 can be set unequal with respect to theaxial direction in accordance with a compressibility and use of thebuffer member. Moreover, a boundary portion between a larger-diameterportion 30 and a smaller-diameter portion 31, and an outercircumferential edge of a larger-diameter portion 30 are rounded ortapered so as to prevent damage to these portions including theoccurrence of cracks therein.

[0061] A contour (contour of larger-diameter portions 30 of the buffermember when the buffer member has larger-diameter portions 30 andsmaller-diameter portions 31) of the buffer member 15 may be formed intoan elliptic shape or an oval shape as shown in FIG. 10 so as to increasethe pressure of the buffer member 15 onto the inner surface of thecylindrical support member 26 measured when the buffer member 15 ispress-fitted in the support member 26 to prevent a relative rotation ofthe buffer member. The buffer member 15 may be bonded to an innersurface of the cylindrical support member 26 with a bonding agent sothat the buffer member cannot be relatively rotated. In the exampleshown in FIG. 10, the interior (square cylinder 28) of the buffer member15 is a cylinder having a cross-sectionally square hollow.

[0062] Two swinging members 25 may also be provided in a bifurcatedstate on one pivot 27.

[0063]FIGS. 11 and 12 show another embodiment of the present invention.A swinging member 25 in this embodiment pivotably supported on a trackframe 2 and supports two rolling wheels 5 at a lower portion thereof.Since the swinging member 25 makes a seesaw movement following a greatlyirregular road surface, the dislocation of the rolling wheel 5 from acrawler 6 is prevented.

[0064] In this embodiment, a cylindrical support member 26 is fixed to alower surface of the track frame 2, a buffer member 15 is fitted intothe support member 26, and a pivot 27 of the swinging member 25 isinserted into the buffer member 15. The buffer member 15 in thisembodiment is formed with larger-diameter portions 30 andsmaller-diameter portions 31 axially alternately arranged in the samemanner as in the above-described embodiment.

[0065] The embodiment of FIGS. 11 and 12 has substantially the sameoperation and effect as the above-described embodiment.

[0066] The present invention is not limited to each of theabove-described embodiments, and the design of the embodiments can besuitably modified.

[0067] For example, the rolling wheels 5 may be straddle rolling wheelswhich roll astride guide projections provided on the innercircumferential surface of the endless crawler 16, or intermediaterolling wheels which roll between a pair of guide projections.

[0068] The rolling wheels 5 may be supported with respect to the trackframe 2 in a center impeller type mode or in a cantilever type mode.

[0069] According to the present invention described in detail above, thevibration of the crawler traveling apparatus can be absorbed properlyowing to the buffer member provided between the track frame and therolling wheels, so that the riding comfort can be improved.

What is claimed is:
 1. A rolling wheel support structure for crawler traveling apparatus, comprising: rotary shafts (10) rotatably supporting rolling wheels (5) which roll on a ground contacting side of an inner circumferential surface of an endless crawler (6); a track frame (2) supporting the rotaty shafts (10); and a buffer member (15) formed of an elastic material and provided between the track frame (2) and the rotary shaft (10).
 2. A rolling wheel support structure for crawler traveling apparatus according to claim 1, wherein the rotary shaft (10) is vertically movably provided on the track frame (2) and provided with a receiving member (14) disposed thereon, and a buffer member (15) disposed between the receiving member (14) and the track frame (2).
 3. A rolling wheel support structure for crawler traveling apparatus, comprising: a swinging member (25) rotatably supporting rolling wheels (5) which roll on a ground contacting side of an inner circumferential surface of an endless crawler (6); a pivot (27) pivotably supporting the swinging member (25); a track frame (2) supporting the pivot (27) thereon; and a buffer member (15) formed of an elastic material and provided between the track frame (2) and the pivot (27).
 4. A rolling wheel support structure for crawler traveling apparatus according to claim 3, wherein the track frame (2) is provided with a cylindrical support member (26) capable of being fitted around the buffer member (15), the buffer member (15) having a cylindrical shape in which the pivot (27) can be held non-rotatably relative to the buffer member (15) around an axis thereof.
 5. A rolling wheel support structure for crawler traveling apparatus according to claim 4, wherein the inner surface of the buffer member (15) is formed into a square cylindrical shape, and the pivot (27) is formed into a square shaft having a cross-section in conformity with that of the cylindrical inner surface of the buffer member (15).
 6. A rolling wheel support structure for crawler traveling apparatus according to claim 4, wherein the buffer member (15) comprises larger-diameter portions (30) and smaller-diameter portions (31) arranged alternately in the axial direction thereof.
 7. A rolling wheel support structure for crawler traveling apparatus according to claim 5, wherein the buffer member (15) comprises larger-diameter portions (30) and smaller-diameter portions (31) arranged alternately in the axial direction thereof.
 8. A rolling wheel support structure for crawler traveling apparatus according to any one of claims 1 to 6, wherein the buffer member (15) is provided correspondingly to a rolling wheel (5) positioned at a front portion or a rear portion of the crawler traveling apparatus.
 9. A rolling wheel support structure for crawler traveling apparatus according to any one of claims 1 to 6, wherein the buffer member (15) is provided correspondingly to a rolling wheel (5) positioned in a longitudinally intermediate portion of the crawler traveling apparatus. 